| 摘要 |
PURPOSE:To improve misconvergence at the intermediate part in the vertical direction of a screen by constructing an auxiliary coil by two pairs of coils generating a quadripole magnetic field and providing at least one of the quadripole coils with a correction circuit which is supplied with electric current when a value for vertical deflection current is higher than a prescribed value. CONSTITUTION:Electric current is caused to flow to a coil 3a of the prestage of a qudripole coil 3 to generate a quadripole magnetic field. Since, when the vertical deflection current is increased and the voltage across a resistance 4b becomes larger than approximately 0.7 V, a diode 4a is actuated, the current is caused to flow to a coil 3b of prestage of a quadripole coil 3. Accordingly, the quadripole magnetic field generated in the correction coil is further increased, thus increasing a correction amount for the vertical line on the screen of an image receiving tube. Thus, when the vertical line forms a barrel type misconvergence pattern, for example, the appropriate correction amount can be obtained at a point where a switching circuit is actuated by properly setting the resistance 4b and a bypass resistance 5. |
